1. Field of the Invention:
This device is designed to provide an easier and more satisfactory method for removing a strip of bark of the proper size from a pine tree precedent to the use of chemicals by known means to induce pine gum flow. This powered tool eliminates problems that have been associated with manual and previous powered methods of preparing a proper wound.
2. Prior Art:
Pine gum (oleoresin) is a basic raw material yielding other products such as turpentine and rosin which are used in the manufacture of many products. Oleoresin is extracted from living pine trees by periodically wounding them and treating the wound with gum flow stimulants to prolong and increase the flow of gum. Such a wound is called a "face" and a face is created by applying a series of bark-removing cuts known as "streaks;" the process of making a streak is known as "chipping." The first streak is made low on the tree trunk near the ground and each successive streak is made directly above the preceding streak at intervals of 2 to 4 weeks during the period from March through October. The gum runs down the face to a collection apron and cup attached to the base of the tree. The face extends to a greater height each time a new streak is cut until it exceeds convenient working reach at which time a new face is begun on the opposite side of the tree to form a "back face."
Each individual streak is made by removing strips of bark 1 to 3 inches high and equal in length to approximately one-third of the circumference of the tree. Ideally, the bark is removed down to the wood surface without penetrating the wood surface. A sulphuric acid solution is then sprayed on the exposed wood to induce and prolong gum flow. A more recent method (patented in December, 1967) utilizes a streak 2 to 3 inches in height; a bead of specially formulated sulphuric acid paste is then applied to the right angle at the top of the streak between the freshly exposed wood and remaining bark. The acid stimulates flow for 2 to 4 weeks at which time a new streak is cut.
The traditional method of chipping is to manually pull a specially shaped blade (hack) across the face of the tree; this action removes a strip of bark 1 to 1 1/2 inches high, but since a proper wound requires a height of 2 to 3 inches, at least two passes must be made to produce one suitable streak. A certain degree of skill is required to cut through all of the bark and not wound the living wood underneath. Because of the degree of skill and the physical effort required to make a proper wound by hand, various alternative methods have been devised.
One of these alternatives was a powered rotary chipper manufactured under the name "J. B. Power Chipper." This chipper was powered by a small gasoline engine. The blade was a solid circular disk with chain-saw teeth riveted to the circumference of the disk. A 3/4-inch wide cut or streak was obtained by using spacers to offset some of the teeth. At the time this device was developed (1958), a 3/4-inch wide streak was adequate to maximize the effectiveness of the chemical spray then being used to promote and prolong gum flow. However, current industry practice is to use an acid paste for gum flow stimulation, and this paste requires a streak 2 to 3 inches wide to maximize its effectiveness. Even if the "J. B. Power Chipper" were still being made, it would be very difficult to increase its effective cutting width to the dimension presently required. Additionally, this device had a marked tendency to bite into the wood, an extremely undesirable trait in itself, but this biting also caused the tool to kickback much as a carpentry bench saw does when put in a bind. The occasional gouging of the wood both increased the risk of infection to the tree as well as produced a very uneven surface over which gum had to flow.
A second, more recent device was issued U.S. Pat. No. 2,932,127 on Apr. 12, 1960. This device, patented by Prance and Sheffield, utilizes a back-mounted gasoline engine driving a remote rotary cutter through a flexible drive shaft. The cutter consisted of a circular disk from the circumference of which protruded four blades each shaped similarly to the blade used with a hand powered bark hack. An L-shaped rod which rode the uncut bark above the intended streak provided the only guide for cutting and also provided the only control for depth of cut. This device also cut a streak of approximately 3/4-inches width, but unlike the "J. B. Power chipper," there was no provision for adjustment of streak width. The entire device weighed approximately 30 pounds.
A primary purpose of this invention is to provide a lighter, more readily portable, and more reliable powered bark hack than presently exists.
Another purpose is to provide a powered bark hack on which the width of cut may be readily and easily varied.
A further purpose is to provide a powered bark hack which requires minimal operator training and skill to produce work of satisfactory quality.
An additional purpose is to provide a powered rotary bark hack which produces a smooth, even cut of proper width and depth with a single pass across the tree face.
Still another purpose is to provide a powered rotary bark hack which conveys chips and debris away from the tree thus eliminating the need for the operator to carry a cover to protect the collection apron and cup from debris.
Additional purposes, features, and advantages will become apparent as the invention is described hereunder.